The present invention relates to a lubricating grease and a process for the preparation thereof. In another aspect, this invention relates to a lubricating grease formed by overbasing a mixture comprising a lubricating oil and an alkaline earth metal sulfonate in the presence of a lower molecular weight sulfonic acid derivative. In still another aspect, this invention relates to the formation of a lubricating grease by treating a lubricating oil and an alkaline earth metal petroleum sulfonate with an alkaline earth metal hydroxide or oxide, carbon dioxide, and an alcohol in the presence of a lower molecular weight sulfonic acid derivative.
Generally, the formation of a lubricating grease requires the use of a thickening agent. It has been found, surprisingly, that upon using a low molecular weight sulfonate in an overbasing process, a material having a grease-like consistency is obtained. Instead of an intractable gel which must be discarded or the normal fluid, overbased oil additive product obtained when employing an overbasing process, the use of a low molecular weight sulfonate in an overbasing process allows one to obtain a lubricating grease which has properties of being highly basic and having a high drop point.
Accordingly, it is an object of this invention to provide a highly basic lubricating grease that does not require a thickening agent.
Furthermore, it is also an object of this invention to provide a novel and simple process for forming a lubricating grease.
It is a further object of this invention to provide a novel and simple process for forming a lubricating grease having the characteristics of high basicity and a high drop point.
It is also an object of this invention to provide a method for inhibiting the corrosion of a surface by depositing on said surface a lubricating grease.
Other objects, aspects, and the several advantages of this invention will be apparent to those skilled in the art upon a study of this disclosure and the appended claims.